The Foreign Ministry rejected on Thursday Australia's groundless move to interfere in China's handling of the case of Chinese-born Australian writer Yang Jun, saying that cases of national security are not open to the public.

Beijing opposes Canberra's meddling in China's judicial sovereignty and has made stern representations to Australia, ministry spokesman Zhao Lijian said at a news briefing.

The Second Branch of the Beijing People's Procuratorate sent the public prosecution of Yang to the Beijing No 2 Intermediate People's Court in October, and the court opened the trial on Thursday.

Yang was charged with espionage and detained in 2019.

Zhao said the court will announce a verdict at a later date.

In response to a report that Australian Ambassador to China Graham Fletcher was denied entry to the Beijing court, Zhao said that "Yang's case involves State secrets; it is reasonable and lawful that it was not heard openly and no one was allowed to observe".

Judicial authorities handled the case in strict accordance with the law and have fully protected Yang's legitimate rights, Zhao said, adding that the authorities have also allowed Australia to receive consular notification and to visit Yang.

According to China's laws, cases involving State secrets are not to be heard in open court and no one is allowed to sit in on the trial, which is a common practice in many countries, Zhao said.